Golf club head with permanent performance indicating indicia

ABSTRACT

A golf club head having a face with a face center and a center face measured performance variable, which may be a characteristic time, or CT, value, a coefficient of restitution, or COR, value, or a potential smash factor. The face includes a center face permanent indicia that is indicative of the center face measured performance variable. Relationships among the permanent indicia and the face are disclosed to reduce the likelihood of distraction caused by the permanent indicia as a golfer addresses a shot. Further, the surface roughness of the permanent indicia is controlled with respect to the surface roughness of the face to reduce the impact that the permanent indicia has on the performance of the golf club head.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. provisional patentapplication Ser. No. 61/846,424, filed on Jul. 15, 2013, all of whichare incorporated by reference as if completely written herein.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

This invention was not made as part of a federally sponsored research ordevelopment project.

TECHNICAL FIELD

The present invention relates to sports equipment; particularly, to agolf club head having permanent performance indicating indicia on theface, a face template containing performance indicating indicia, anelectronic face template containing performance indicating indicia thatis unique for each golf club head, and/or a method of selling golf clubsbased on a performance characteristic of the golf club head.

BACKGROUND OF THE INVENTION

In 1998 the United States Golf Association (USGA) limited thecoefficient of restitution (COR) in drivers to 0.830, more specificallyto 0.822 with a test tolerance of 0.008 effectively taking the limit upto 0.830. With the introduction of these limits, The USGA needed a testprocedure to measure a driver's COR. Originally, a ball was fired by aircannon into a specimen and pre and post impact velocities were comparedto find COR, as set forth in “Procedure for Measuring the Velocity Ratioof a Clubhead for Conformance to Appendix II, (5a.),” Revision 3 Jan. 1,2002. This process took a significant amount of time to perform whenconsidering the set up and the controls associated with the test.

Those skilled in the art know that today the characteristic time, oftenreferred to as the CT, value of a golf club head is more widely used indetermining conformance with the USGA equipment rules. The rulescurrently state that the characteristic time, or CT, of a club headshall not be greater than 239 microseconds, with a maximum testtolerance of 18 microseconds. Thus, it is common for golf clubs to bedesigned with the goal of a 239 microsecond CT, knowing that due tomanufacturing variability that some of the heads will have a CT valuehigher than 239 microseconds, and some will be lower. However, it iscritical that the CT value does not exceed 257 microseconds or the clubwill not conform to the USGA rules. The USGA publication “Procedure forMeasuring the Flexibility of a Golf Clubhead,” Revision 2.0, Mar. 25,2005, is the current standard that sets forth the procedure formeasuring the characteristic time. However, this CT test is onlyapplicable to drivers and the USGA still employs the air cannon COR testwhen testing fairway woods, hybrids and irons.

Another common golf club performance variable is the smash factor, orSF. The smash factor is defined as the ratio of ball speed to club headspeed and may be used as a measure of the quality of ball striking.First, one must look to the ball speed formula, specifically:

Vball=Vch*[(1+COR)/(1+(Mball)/(Mch))]*cos(loft) (1−0.14*miss)

where:

-   -   Vball is the velocity of the ball immediately after impact with        the club head.    -   Vch is the velocity at of the club head at impact with the golf        ball.    -   Mball is the mass of the golf ball, most commonly approximately        46 grams.    -   Mch is the mass of the club head in grams.    -   “miss” is the distance, in inches, that impact misses the face        center.    -   COR is the coefficient of restitution measured at the face        center.

Since the smash factor (SF) is the ratio of the ball speed to the clubhead speed, the equation for smash factor (SF) is:

SF=(Vball/Vch)=[(1+COR)/(1+(Mball)/(Mch))]*cos(loft)*(1−0.14*miss)

Thus, the potential smash factor (SF) at any point on the face can bedetermined and is very club head specific since it takes into accountthe particular golf club head's COR, mass, and loft.

Currently, most golf club heads that are sold to the general golfingpopulation are not individually tested to determine each golf clubhead's CT, or COR, or potential SF value(s). Generally, a random samplewill be taken off the manufacturing line and tested to determineconformance of a much larger lot of heads. Thus, it is not uncommon forgolf club heads having nonconforming CT, or COR, values to make it tothe market. In fact, in the past decade at least two major golfequipment companies have issued recalls on their products because headswith higher than allowable CT value have made it into the hands ofgolfers. Such product recalls are incredibly expensive and result intremendous waste, not to mention the impact upon consumer confidence.

Numerous production variables influence the final COR and CT values of agolf club head, as well as the potential SF values. Today, most driverheads are composed of several individual components joined together tocreate a golf club head. Often times the golf club's sole, crown, andface are distinct components, often made of dissimilar materials and/orthicknesses, which are joined together to create the final product.Generally the metallic components are welded or brazed together, and thenon-metallic components are joined to metallic components by adhesives.One skilled in the art will appreciate that manufacturing variables suchas the quality of a weld, the amount of brazing material, and adhesivequality and curing, just to name a few, can influence the finalperformance of a golf club head, including the COR, CT, and potential SFvalues. Further, variability in the composition of the alloys used toform the various components may influence the performance variables, ascan unintended variations from the design thickness of the componentsintroduced during casting or forging. Because of these factors, one golfclub head design that is produced at two different manufacturingfacilities may have significantly different COR and CT values. Thus, thereal COR and/or SF and/or CT value of a golf club head cannot beaccurately determined until the head is fully assembled in its finalform.

A consumer purchasing a golf club often has no idea if the particulargolf club head they are purchasing has a CT value or COR value withinthe USGA limit, above the limit, or well below the limit. Utilizing aclub head with a value above the limit during tournament play couldresult in the disqualification of a golfer; whereas using a club headwith a value below the limit means that the golfer is possiblyhandicapping themselves with respect to the rest of the field.Additionally, the purchaser generally has no idea how the CT, COR,and/or potential SF values vary at particular locations across the faceof the golf club head. Therefore, the need exists for a method ofidentifying and marking the CT, COR, or potential SF value on the faceof a golf club head, either permanently or via a removable facetemplate.

SUMMARY OF THE INVENTION

A method of identifying and marking a measured performance variable,such as the CT value, COR value, potential smash factor, etc., of atleast one location on the face of a golf club head, either permanentlyor via a removable face template, thereby enabling a significant advancein the state of the art; a golf club head having performance indicatingindicia on the face; a method for creating same; and a method of sellinggolf clubs based upon a measured performance variable.

BRIEF DESCRIPTION OF THE DRAWINGS

Without limiting the scope of the present invention as claimed below andreferring now to the drawings and figures:

FIG. 1 shows a front elevation view of a golf club head of the presentinvention, not to scale;

FIG. 2 shows a front elevation view of a golf club head of the presentinvention, not to scale;

FIG. 3 shows a front elevation view of a golf club head of the presentinvention, not to scale;

FIG. 4 shows a center face vertical cross-sectional view of a golf clubhead of the present invention, not to scale;

FIG. 5 shows a center face vertical cross-sectional view of a golf clubhead of the present invention, not to scale;

FIG. 6 shows a center face vertical cross-sectional view of a golf clubhead of the present invention, not to scale;

FIG. 7 shows a front elevation view of a golf club head of the presentinvention, not to scale;

FIG. 8 shows a front elevation view of a golf club head of the presentinvention, not to scale;

FIG. 9 shows a front elevation view of a golf club head of the presentinvention, not to scale;

FIG. 10 shows a front elevation view of a golf club head of the presentinvention, not to scale;

FIG. 11 shows a front elevation view of a golf club head of the presentinvention, not to scale;

FIG. 12 shows a front elevation view of a golf club head of the presentinvention, not to scale;

FIG. 13 shows a front elevation view of a golf club head of the presentinvention, not to scale;

FIG. 14 shows a front elevation view of a golf club head of the presentinvention, not to scale;

FIG. 15 shows a front elevation view of a golf club head of the presentinvention, not to scale;

FIG. 16 shows a front elevation view of a golf club head of the presentinvention, not to scale;

FIG. 17 shows a schematic view of several items used in a method of thepresent invention, not to scale;

FIG. 18 shows a front elevation view of a golf club head of the presentinvention, not to scale;

FIG. 19 shows a front elevation view of a golf club head of the presentinvention, not to scale; and

FIG. 20 shows a front elevation view of a golf club head of the presentinvention, not to scale.

These drawings are provided to assist in the understanding of theexemplary embodiments of the invention as described in more detail belowand should not be construed as unduly limiting the invention. Inparticular, the relative spacing, positioning, sizing and dimensions ofthe various elements illustrated in the drawings are not drawn to scaleand may have been exaggerated, reduced or otherwise modified for thepurpose of improved clarity. Those of ordinary skill in the art willalso appreciate that a range of alternative configurations have beenomitted simply to improve the clarity and reduce the number of drawings.

DETAILED DESCRIPTION OF THE INVENTION

The present method of identifying and marking a measured performancevariable, such as the CT value, COR value, potential smash factor, etc.,of at least one location on the face of a golf club head, eitherpermanently or via a removable face template, thereby enabling asignificant advance in the state of the art; a golf club head havingperformance indicating indicia on the face; a method for creating same;and a method of selling golf clubs based upon a measured performancevariable. The preferred embodiments of the invention accomplish this bynew and novel arrangements of elements and methods that are configuredin unique and novel ways and which demonstrate previously unavailablebut preferred and desirable capabilities. The description set forthbelow in connection with the drawings is intended merely as adescription of the presently preferred embodiments of the invention, andis not intended to represent the only form in which the presentinvention may be constructed or utilized. The description sets forth thedesigns, functions, means, and methods of implementing the invention inconnection with the illustrated embodiments. It is to be understood,however, that the same or equivalent functions and features may beaccomplished by different embodiments that are also intended to beencompassed within the spirit and scope of the invention.

The present invention includes a golf club head with permanentperformance indicating indicia on the face and a method of making thegolf club head. As explained in the “Background of the Invention”section above, despite all the technical advances in the field of golfequipment, it is difficult, if not impossible, to predict the true finalcharacteristic time, often referred to as the CT, or the finalcoefficient of restitution, often referred to as the COR, of a golf clubhead via computer modeling. The fact is that too many production andmanufacturing variables influence the final CT and/or COR of anassembled golf club head.

FIG. 1 illustrates a golf club head (100) having a face (200) and a facecenter (250). One skilled in the art will recognize that the face center(250), as used herein, may be located using the USGA method described inthe United States Golf Association publication, “Procedure for Measuringthe Flexibility of a Golf Club head,” Revision 2.0, Section 6.1 (Mar.25, 2005). As described in this procedure the face center (250), maybelocated using a template, having a coordinate system with a heel-toeaxis orthogonal to a sole-crown axis. An aperture may be located at theorigin of the coordinate system and each axis may be divided into evenlyspaced increments. The template may be composed of a flexible material,e.g., a transparent polymer. The template is used as follows: 1) Thetemplate is placed on the face (200) with the heel-toe axissubstantially parallel to the leading edge. The template is then movedback and forth in the heel-toe direction along the face (200) until theheel and toe measurements at the opposite edges of the face (200) areequal. 2) The template is moved back and forth in the sole-crowndirection along the face (200) until the sole and crown measurements atthe opposite edges of the face (200) are equal. 3) The template is movedwith respect to the face (200) as described in steps 1 and 2, above,until the heel and toe as well as the sole and crown measurements alongthe corresponding axes are equal. A point is then marked on the face(200) through the aperture to indicate the face center (250). The sameUSGA publication identifies the procedure for determining thecharacteristic time at the face center (250), referred to herein as thecenter face CT. The same procedure may be used to determine thecharacteristic time, or CT, of any point on the face (200) of the golfclub head (100) after it is fully assembled, finished, and ready foruse.

FIG. 2 illustrates a golf club head (100) with the center face (250)identified and having a center face permanent indicia (252) with acenter face indicia surface area (258), wherein the center facepermanent indicia (252) is indicative of the measured center face CTthat may be unique to each individual golf club head (100). Similarly,the embodiment of FIG. 19 illustrates a golf club head (100) with thecenter face (250) identified and having a center face permanent indicia(252) with a center face indicia surface area (258), wherein the centerface permanent indicia (252) is indicative of the measured center faceCOR that may be unique to each golf club head (100). Further, in yetanother embodiment, not illustrated but easily understood, the golf clubhead (100) has a center face permanent indicia (252) that is indicativeof the potential smash factor (SF), which takes into account themeasured center face COR, the measured mass of the golf club head (100),and the measured loft. This embodiment is particularly relevant to aparticular golf club head (100) because although there is a “design”club head mass and loft, the actual club head mass and loft of thefinished golf club head (100) is rarely equal to the design values.Thus, in a variation of this embodiment separate measured club head masspermanent indicia and measured loft permanent indicia may also be on thegolf club head (100), although not necessarily on the face (200).

The center face permanent indicia (252) can include numerals, letters,symbols, and/or changes in, or on, the surface of the face (200) thatare indicative of the measured center face CT. In the embodiment of FIG.2 the measured center face CT was 245 microseconds and the center facepermanent indicia (252) consists of the marking “245 CT,” or simply“245,” which allows the purchaser to know the exact CT of the club head(100) that they are purchasing and the point on the face (200) at whichit was measured. An alternative center face permanent indicia (252) thatis indicative of the measured center face CT is shown in FIG. 3consisting of the marking “+6,” showing the consumer that the centerface CT is 6 microseconds above the USGA limit of 239 microseconds, butstill within the maximum test tolerance of 18 microseconds. Thus, inthis example a threshold CT value is the 239 microsecond value and thecenter face permanent indicia (252) is identifying the differencebetween the measured center face CT and the threshold value. One skilledin the art will appreciate that the threshold value is not limited tothe 239 microsecond value, but may be any preset value that allows aconsumer to then determine the center face CT that was actually measuredfor a particular golf club head (100).

An even further alternative embodiment may incorporate center facepermanent indicia (252) that is indicative of the measured center faceCT that consists of the marking “−12,” indicating to the consumer thatthe center face CT is 12 microseconds below the USGA limit of 239microseconds plus the 18 microsecond tolerance. Yet another embodimentmay simply incorporate center face permanent indicia (252) that isindicative of the measured center face CT that consists of a markingsuch as “MAX” if the measured center face CT is at, or above, 239microseconds; or even further such a “MAX” marking may be reserved forif the measure center face CT is at the absolute 257 microsecond limit.In the embodiments utilizing letters, numbers, and/or symbols as thecenter face permanent indicia, the center face indicia surface area isdefined by area on the face (200) enclosed by the smallest imaginaryrectangular box drawn on the face (200) that totally encloses the centerface permanent indicia (252), as seen in FIG. 2.

Likewise, in the embodiment of FIG. 19 the measured center face COR was0.825 and the center face permanent indicia (252) consists of themarking “0.825 COR,” or simply “0.825,” which allows the purchaser toknow the exact COR of the club head (100) that they are purchasing andthe point on the face (200) at which it was measured. An alternativecenter face permanent indicia (252) that is indicative of the measuredcenter face COR is shown in FIG. 20 consisting of the marking “−0.005,”showing the consumer that the center face COR is 0.005 units below theUSGA limit of 0.830. Alternatively the center face permanent indicia(252) may consist of the marking “+0.003,” showing the consumer that thecenter face COR is 0.003 units above the USGA limit of 0.822, but stillwithin the maximum test tolerance of 0.008. Further, any of these CORembodiments may multiply by a factor of 10 to simply the center facepermanent indicia (252). For example, multiplying by 1000 wouldfacilitate the use of a “825” marking, or a “−5” marking, or a “+3”marking.

Further, the golf club head (100) may have center face permanent indicia(252) that is indicative of the potential smash factor (SF), therebytaking into account the measured center face COR, the measured mass ofthe golf club head (100), and the measured loft. As previouslyexplained, the small factor (SF) may be calculated by:

SF=(Vball/Vch)=[(1+COR)/(1+(Mball)/(Mch))]*cos(loft)*(1−0.14*miss)

For example, taking an ideal impact with a “miss” value of zero, a CORof 0.830, a golf club head (100) mass of 200 grams, and a loft of 10degrees, the potential smash factor (SF) at the center face is:

SF=[(1+0.830)/(1+(46)/(200))]*cos(10)*(1−0.14*0)=1.465

The potential smash factor (SF) for a specific individual golf club headis valuable to a consumer because the use of launch monitors is becomingincreasingly common and such launch monitors generally determine theactual smash factor for a particular impact. Therefore, without knowingthe potential smash factor (SF) of the golf club head that a golfer isusing during testing with a launch monitor, thereby taking into accountthe specific measured club head COR, mass, and loft, the golfer reallyhas no idea of how close they are to achieving an ideal impact. Forinstance, in the example above the potential small factor (SF) is 1.465;if a golfer is blindly receiving a reading from a launch monitor of anactual impact's smash factor of 1.4 the golfer may mistakenly believethat an ideal smash factor should be over 1.5, which is a value that isactually not obtainable with this particular golf club head.

Further, in this one example the center face permanent indicia (252) maybe a numerical marking of 1.465. The small factor (SF) is a useful toolin that smash factor values may be calculated for multiple locations onthe face (200) once the center face COR is measured. For instance, inthis example a point 0.75 inches from the face center (250) would have asmall factor (SF) of:

SF=[(1+0.830)/(1+(46)/(200))]*cos(10)*(1−0.14*0.75)=1.311

Further embodiments of the center face permanent indicia (252) may notinclude any numerals or letters, but may consist entirely of symbolsthat are indicative of the measured center face CT. In yet a furtherembodiment the center face permanent indicia (252) may be a perimetercontour line indicating the area of the face (200) that has a prescribedmeasured CT value, COR value, or potential smash factor (SF) value. Inthis embodiment the center face permanent indicia (252) is similar tothe highest elevation of a topographic map with contour lines.Alternative embodiments may include additional permanent indicia in theform of contour lines to allow a consumer to view how the measured CT,COR, or potential SF varies across the face (200) of a particular golfclub. Such additional permanent indicia contour lines may be shown inincrements of 1 microsecond, 2 microseconds, 5 microseconds, or even 10microseconds. Alternatively, such additional permanent indicia contourlines may be shown in increments of 0.005 COR, 0.01 COR, 0.02 COR, oreven 0.05 COR. Alternatively, such additional permanent indicia contourlines may be shown in increments potential smash factor such as 0.005,0.01, 0.02, or even 0.05. In such a contour line embodiment thepermanent indicia surface area is not determined using the rectangularbox technique previously identified; rather it is the actual surfacearea of the perimeter contour line. For example, if the contour line is1 mm wide and has a length of 25 mm then the permanent indicia surfacearea is simply 25 mm², not the area enclosed by the contour line.

Alternatively, in yet a further embodiment the center face permanentindicia (252) may consist of variations of the face surface in lieu of adistinct a perimeter contour line, as described above, whiletransmitting the same information to the consumer regarding the actualmeasured performance characteristic of a particular golf club head(100), whether it be CT, or CT profile, COR, or COR profile, or SF, orSF profile. Such permanent indicia surface variations may be achievedwith a change in surface texture, brushing, polishing, gloss, and/orcolor.

The reference used throughout to “permanent indicia” is specificallydefined as indicia that is still recognizable, after 500 impacts with agolf ball traveling at 100 miles per hour targeted at the geometriccenter of the indicia, by a majority of a pool of 100 test subjects with20/20 vision, when viewed at a distance of 24 inches from their eyes.

The center face permanent indicia (252) need not include a change in thesurface elevation of the face (200). However, some embodiments the golfclub head (100) have at least a portion of the face (200) covered with aface coating (290) having a coating thickness (292). In such embodimentsthe center face permanent indicia (252) may be formed in the facecoating (290). The face coating (290) may be applied to the golf clubhead (100) through any number of processes including, but not limitedto, physical vapor deposition (PVD) and chemical vapor deposition (CVD).In one embodiment the coating thickness (292) is 0.3-15 microns.

The center face permanent indicia (252) may have a center face indiciadepth (256) that is less than the coating thickness (292) as seen inFIG. 4, less than 50% of the coating thickness (292) in someembodiments, and between 5-50% of the coating thickness (292) in afurther embodiment. Conversely, in other embodiments the center faceindicia depth (256) may be greater than the coating thickness (292) asseen in FIG. 6, thereby exposing a portion of the parent face material,which in some embodiments may then be covered with a paint-fill process.The paint, ink, and/or coating used for any of the permanent indicia,whether on the surface or recessed, may be a color changing paint inwhich the color of the material changes with the angle of observance.Thus, in one embodiment when viewed from the address position, the coloris low contrast with respect to the face (200), while when viewing thegolf club head (100) face-on the color is medium to high contrast withrespect to the face. In this embodiment, when viewed from the butt ofthe golf grip the difference between the center face permanent indiciaL* value and the face L* value is less than 25; however when viewing theface (200) perpendicular to the line of sight the difference between thecenter face permanent indicia L* value and the face L* value is at least30. In further embodiments the paint, ink, and/or coating used for anyof the permanent indicia, whether on the surface or recessed, may beindiscernible to naked eye in certain conditions while easilydiscernable to the naked eye in other conditions, including, but notlimited to, paints, inks, coatings, and/or adhesives that are onlyvisible under the ultraviolet light. Further, the paint, ink, and/orcoating used for any of the permanent indicia, whether on the surface orrecessed, may be include hydrophilic and/or hydrophobic attributes.Accordingly, certain areas of the face may have a higher level ofhydrophilicity than the level of hydrophilicity of other areas of theface. Hydrophilic means attracting water and hydrophobic means repellingwater. Thus, the permanent indicia may be indiscernible when the face isdry but when the face brushed with a wet towel the water may beattracted to the permanent indicia such that a golfer can easilyidentify the permanent indicia.

Further, as seen in FIG. 5, the center face indicia depth (256) may becarefully controlled so that it is approximately equal to the coatingthickness (292). The center face indicia depth (256) is important toensuring the durability of the face (200) and avoidance of the formationof stress fractures on the face (200). This is particularly true nearthe center face (250). Thus, maintaining a very small center faceindicia depth (256) ensures that the thickness of the face (200) doesnot need to be increased to accommodate the center face permanentindicia (252). The center face indicia depth (256) is preferably lessthan about 0.15 mm.

In some embodiments the face (200) simply has a polished, or brushed,metal finish, while other embodiments are directed to golfers thatprefer a darker face (200), which is increasingly common today with golfclub heads having white or colored crowns due to an improvement in theability to align the golf club head. While providing contrasting darkareas facilitates a golfer's perception of a golf club, clubs such asdrivers, fairway woods, and hybrid/utility clubs (“wood-style clubs”) donot typically include the substantial number of alignment aids.Alignment of wood-style clubs is especially important because if thestriking surface is not properly aligned at impact, then the landingposition of the ball will be farther off-line than shots with irons or aputter with equivalent impact misalignments. For example, if a driver ismisaligned so as to be 2 degrees open at impact, the struck ball willend up about 24 yards off-line relative to the intended path, assumingan initial ball speed of 145 mph. Similarly, if a 6-iron is 2 degreesopen relative at impact, the struck ball will end up about 13 yardsoff-line, and a wedge at 2 degrees open would be 2 yards off-line. Inorder to return the club to square at impact, the club face ispreferably precisely aligned at address, prior to impact. For mostgolfers, a repeatable swing is difficult to achieve, and without arepeatable address alignment, even a repeatable swing will not producerepeatable results.

The face coating (290) may be a dark diffusely reflecting surface havinga chroma value of less than 1. Further, the face coating (290) may havea CIELab brightness of less than 40, and may further have a gloss valueof less than 60 gloss units. Since alignment of the golf club head (100)is so important, it is desirable that the center face permanent indicia(252) does not distract the golfer, particularly since the golfer isgenerally focused on the vicinity of the center face (250) at addressand the center face permanent indicia (252) is often not symmetrical. Asthe loft of a golf club head (100) increases the golfer is able to seemore of the face (200), and is more likely to notice the center facepermanent indicia (252), at address. Thus, one embodiment incorporateslow to medium contrast between the face (200) and the center facepermanent indicia (252). In this embodiment the center face permanentindicia (252) has a center face permanent indicia CIELab L* value, theface (200) has a face CIELab L* value, and the difference between thecenter face permanent indicia L* value and the face L* value is relatedto the volume and the loft of the golf club head (100). In oneembodiment the difference in L* value is governed by the equationΔL*≦[(volume)/100×(loft)]. Thus, a large volume low lofted golf clubhead (100) such as a 9 degree 460 cc driver is able to accommodate alarger difference between the center face permanent indicia L* value andthe face L* value, without being distracting to the golfer at address.Further, a smaller volume higher lofted golf club head (100) such as a21 degree 100 cc hybrid type golf club head may support less of adifference between the center face permanent indicia L* value and theface L* value, without being distracting to the golfer at address. Aneven less potentially distracting embodiment the difference in L* valueis governed by the equation ΔL*≦[(volume)/125×(loft)]. A furtherembodiment reduces the potential for distraction by maintaining thedifference between the center face permanent indicia L* value and theface L* value at less than 25; and another embodiment produces a verylow contrast with the difference between the center face permanentindicia L* value and the face L* value is less than 10. In an evenfurther embodiment the center face permanent indicia CIELab L* valuechanges throughout the center face permanent indicia (252). Such avarying center face permanent indicia CIELab L* value may make thecenter face permanent indicia (252) less noticeable to golfers when inthe address position, while remaining easily discernable when holdingthe face (200) directly in front of them. In one variation of thisembodiment the highest center face permanent indicia CIELab L* value islocated at the lowest portion of the center face permanent indicia (252)and the L* value decreases as the elevation of the ground plane (GP)increases.

In order to further aid in a golfer's alignment, some embodiments of thegolf club head (100) include at least one linear face marking (280)having a linear face marking L* value, as seen in FIG. 2 and oftenreferred to as a score line or groove. In this embodiment a highercontrast between the linear face marking (280) and the face (200) isdesirable so a golfer can easily distinguish this feature that may aidin alignment and reduce the likelihood of the golfer focusing on thecenter face permanent indicia (252). Thus, the difference between thelinear face marking L* value and the face L* value is at least 30.

The at least one linear face marking (280) may include numerous distinctlinear face markings (280) as seen in FIG. 2. Whether the at least onelinear face marking (280) is a single marking or multiple markings,there will be a total linear face marking surface area (284). Forexample, if a face (200) contains at least one linear face marking (280)with a total length of 250 mm and a width of 1 mm then the total linearface marking surface area (284) is 250 mm² Since the at least one linearface marking (280) aids a golfer in alignment and takes the golfer'sfocus off the center face permanent indicia (252), in one embodiment itis preferred to have the center face indicia surface area (258) lessthan the linear face marking surface area (284). In an even furtherembodiment the center face indicia surface area (258) is less than 50%of the linear face marking surface area (284).

However, reducing the center face indicia surface area (258) too far hasdiminishing returns and the center face indicia surface area (258)should remain large enough to be easily identifiable when a golfer holdsthe golf club head (100) with the face (200) pointing at the golfer,while remaining small enough to not distract the golfer when looking atthe golf club head (100) while addressing a golf ball. Therefore, in oneembodiment the center face indicia surface area (258) remains at least15% of the linear face marking surface area (284). An additionalembodiment relates the center face indicia surface area (258) to thestriking surface area (232) within 0.75 inches of the center face (250).In this embodiment the center face indicia surface area (258) is atleast 3% of the striking surface area (232) within 0.75 inches of thecenter face (250). Skilled golfers are more likely to noticenontraditional markings on the face (200) at address, therefore inanother embodiment the center face indicia surface area (258) is cappedto be less than 20% of the striking surface area (232) within 0.75inches of the center face (250).

Since at least one linear face marking (280) may be incorporated intothe golf club head (100) to reduce the likelihood that a golfer isdistracted by the center face permanent indicia (252) while addressing agolf ball, a further embodiment positions the at least one linear facemarking (280) so that a portion of it is vertically below a portion ofthe center face permanent indicia (252). An alternative embodimentpositions the at least one linear face marking (280) so that a portionof it is vertically above a portion of the center face permanent indicia(252), while an even further embodiment positions the at least onelinear face marking (280) so that a portion of it is vertically below aportion of the center face permanent indicia (252) and a portion of itis vertically above a portion of the center face permanent indicia(252). The spacing of the at least one linear face marking (280) aboveand/or below the center face permanent indicia (252) may be such thatthe vertical separation distance from the portion of the linear facemarking (280) to the imaginary rectangular box, illustrated in FIG. 2,used to define the center face indicia surface area (258), is at least0.5 inches to resemble a more traditional appearance. However, in oneembodiment the spacing of the at least one linear face marking (280)above and/or below the center face permanent indicia (252) is such thatthe vertical separation distance is less than 0.25 inches to evenfurther obscure the center face permanent indicia (252) when viewing theface (200) from the address position.

To further instill consumer confidence in the testing and marking ofeach unique golf club head (100), a further embodiment includes apermanent center face indicator at the location of the face center (250)to illustrate the exact point on the face (200) that the center face CTwas measured. For instance, FIG. 2 illustrates the permanent center faceindicator as a simple dot or circle, although it could also berepresented with cross-hairs, an arrow, or any easily identifiablesymbol.

As previously noted, in some embodiments the center face permanentindicia (252) is formed in the face (200) or the face coating (290) byremoving a portion of the face (200) or the face coating (290), therebyproducing a center face indicia depth (256) that may be constant orvary. Further, some embodiments incorporate at least one linear facemarking (280) that may be a simple marking on the face (200) or may beformed in the face (200), or face coating (290), to produce a linearface marking depth (282). One particular durable embodiment has amaximum center face indicia depth (256) that is less than the maximumlinear face marking depth (282), while a further embodiment keeps themaximum center face indicia depth (256) at less than 50% of the maximumlinear face marking depth (282), and an even further embodimentmaintains the maximum center face indicia depth (256) at less than 10%of the maximum linear face marking depth (282). The maximum linear facemarking depth (282) is preferably less than 0.2 mm.

As one skilled in the art will understand, the face (200) of every golfclub head (100) has a face surface roughness and a face area. Further,the center face permanent indicia (252) has a permanent indicia surfaceroughness. A golf club head (100) with a large face area and low loftcan support a larger difference between the permanent indicia surfaceroughness and the face surface roughness with minimal impact on theflight characteristics of a golf ball struck by the golf club head(100). In one embodiment the difference between the permanent indiciasurface roughness and the face surface roughness is related to the loftand the face area by the equation ΔSR≧[60*(face area)/(loft)], for loftsless than 25 degrees, wherein the permanent indicia surface roughness isgreater than the face surface roughness. For example, a 460 cc driverhaving a loft of 10 degrees and a face area of 6.8 square inches has thedifference between the permanent indicia surface roughness and the facesurface roughness of ΔSR≧[60*(6.8)/(10)], or a ΔSR≧40.8 μin. In anotherexample, a 150 cc three wood having a loft of 15 degrees and a face areaof 2.9 square inches has the difference between the permanent indiciasurface roughness and the face surface roughness of ΔSR≧[60*(2.9)/(15)],or a ΔSR≧11.6 μin. In a further example, a 100 cc hybrid 3-iron having aloft of 21 degrees and a face area of 3.6 square inches has thedifference between the permanent indicia surface roughness and the facesurface roughness of ΔSR≧[60*(3.6)/(21)], or a ΔSR≧10.3 μin.

In a further embodiment the permanent indicia surface roughness of atleast 10 μin greater than the adjacent face surface roughness, and insome embodiments with very low face surface roughness the permanentindicia surface roughness may be at least twice the adjacent facesurface roughness. In a further low face surface roughness faceembodiment it is preferred to have a permanent indicia surface roughnessof less than fifteen times the adjacent face surface roughness. In oneparticular embodiment a polished PVD face of the golf club head (100)may have a face surface roughness of about 7 μin, whereas the permanentindicia surface roughness may be about 77 μin. In another embodiment theface surface roughness is preferably 5-70 μin when measured in aparallel direction to the grooves, and the permanent indicia surfaceroughness is preferably 50-90 μin when measured in a parallel directionto the grooves.

Conversely, in another embodiment, higher lofted golf club heads (100),namely those with a loft of at least 25 degrees, preferably have asmaller difference between the permanent indicia surface roughness andthe face surface roughness. In this embodiment the difference betweenthe face surface roughness and the permanent indicia surface roughnessis related to the loft and the face area by the equation ΔSR≦[200*(facearea)/(loft)], wherein the face surface roughness is greater than thepermanent indicia surface roughness. Such higher lofted clubs aregenerally iron golf club heads (100) that do not have a polished face(200) and may have a textured face (200). Therefore, the face surfaceroughness may be reduced by the addition of the center face permanentindicia (252), which is undesirable in higher lofted golf club heads(100) where increased spin is desirable. For example, a 5-iron having aloft of 27 degrees and a total face area of 4.6 square inches has thedifference between the permanent indicia surface roughness and the facesurface roughness of ΔSR≦[200*(4.6)/(27)], or a ΔSR≦34 μin. In oneparticular embodiment, an iron type golf club head (100) may have a facesurface roughness of about 20-200 μin when measured in a paralleldirection to the grooves, whereas the permanent indicia surfaceroughness may be less than face surface roughness, but preferably withinthe 34 pin calculated using the above equation. In another embodimentthe face surface roughness is preferably 70-100 μin when measured in aparallel direction to the grooves, and the permanent indicia surfaceroughness is preferably 50-90 μin when measured in a parallel directionto the grooves. The surface finishes discussed above may vary dependingon design choice and the examples given do not limit the types ofsurface finishes that may be used with this invention. Known surfacefinishes include: no plating or a hot oil finish that is designed to ruboff, exposing the underlying metallic club head material, resulting inrust; nickel plating of various colors; anodizing of various colors;chrome plating; media blasting; and etching, just to name a few.Further, the surface roughness of the surface finishes discussed abovemay vary depending on design choice and examples given do not limit therange of surface roughness that may be used with this invention. Forexample, smooth or shiny surface finishes will have a small surfaceroughness value and will generally result in less friction. Rough,textured or matte finishes will have a larger surface roughness valueand will generally result in more friction. Further the face (200) maybe textured, milled, cast, or otherwise created to have surface featuresor patterns that would create greater friction when compared to asimilar face (200) with the same measured surface roughness but withoutthe textured, milled, cast or otherwise created surface features orpatterns.

Other permanent indicia, separately or together, may be incorporated infurther embodiments. All of the disclosure directed to the center facepermanent indicia (252) and the various relationships of the coating(290); the coating thickness (292); the center face indicia depth (256);the chroma value; the permanent indicia surface roughness; the permanentindicia surface area; the face surface roughness; the differences insurface roughness; the volume; the loft; the brightness; the glossunits; the L* values; the differences in the permanent indicia L* valueand the face L* value; the at least one linear face marking (280); thelinear face marking surface area (284); the face surface area; thelinear face marking L* value; the at least one linear face marking(280), its location, surface area, and depth (282); and theconstruction, make-up, depth, and roughness of the permanent indicia;equally apply to a first permanent indicia (310), a second permanentindicia (410), a third permanent indicia (510), a fourth permanentindicia (610), and a max performance permanent indicia (710), but willnot be repeated for each permanent indicia in the sake of brevity.

For instance, one embodiment of the golf club head (100) may have afirst permanent indicia (310) located on a face toe portion (260) of theface (200) indicative of a first CT, COR, or potential SF measured at afirst face point (300), or calculated based upon at least one measuredvalue, located on a face toe portion (260), as seen in FIG. 8. The firstpermanent indicia (310) may be the only permanent indicia on the golfclub head (100), or may be incorporated with one or more of the otherdisclosed permanent indicia. In this embodiment the face (200) has afirst thickness (320) at the first face point (300), and the firstpermanent indicia (310) has a first indicia surface area (340). In oneparticular embodiment the golf club head (100) includes at least thecenter face permanent indicia (252) and the first permanent indicia(310), and the location of the first permanent indicia (310) is suchthat the first thickness (320) is different than the center facethickness (254). In another embodiment having both the center facepermanent indicia (252) and the first permanent indicia (310), the firstface point (300) is located higher on the face (200) than the facecenter (250), as seen in FIG. 8.

Similarly, another embodiment of the golf club head (100) may have asecond permanent indicia (410) located on a face heel portion (270) ofthe face (200) indicative of a second CT, COR, or potential SF measuredat a second face point (400), or calculated based upon at least onemeasured value, located on a face heel portion (270), also seen in FIG.8. The second permanent indicia (410) may be the only permanent indiciaon the golf club head (100), or may be incorporated with one or more ofthe other disclosed permanent indicia. In this embodiment the face (200)has a second thickness (420) at the second face point (400), and thesecond permanent indicia (410) has a second indicia surface area (440).In one particular embodiment the golf club head (100) includes at leastthe center face permanent indicia (252) and the second permanent indicia(410), and the location of the second permanent indicia (410) is suchthat the second thickness (420) is different than the center facethickness (254). In another embodiment having both the center facepermanent indicia (252) and the second permanent indicia (410), thesecond face point (400) is located lower on the face (200) than the facecenter (250), as seen in FIG. 8.

Even further, another embodiment of the golf club head (100) may have acenter face permanent indicia (252), a first permanent indicia (310)located on the face toe portion (260), and a second permanent indicia(410) located on a face heel portion (270). In a variation of thisembodiment the first face point (300) is located higher on the face(200) than the face center (250), and the second face point (400) islocated lower on the face (200) than the face center (250), as seen inFIG. 8, thereby informing the consumer of the actual measure performanceof the golf club head (100) throughout a common impact pattern oflow-heel impacts to high-toe impacts. In a further variation of thisembodiment at least one of the first thickness (320) or the secondthickness (420) is different from the center face thickness (254); whilein a further embodiment both the first thickness (320) and the secondthickness (420) are different from the center face thickness (254), andthe first thickness (320) is different than the second thickness (420).

Still further, any of the embodiments having a first permanent indicia(310) or a second permanent indicia (410), either alone, together, or incombination with other permanent indicia, may position the firstpermanent indicia (310) and/or the second permanent indicia (410) on theface (200) to provide the consumer with an indication of how the actualclub head specific CT, COR, or potential SF varies at a point, orpoints, near a face perimeter (210). For example, consumers expectequipment companies to achieve reasonably high CT, COR, or potential SFvalues at the face center (250), although consumers rarely fullyappreciate the variations from club head to club head. However mostgolfers do not consistently impact the golf ball at the face center(250) and therefore may be better served by knowing the actual measuredCT, COR, or calculated potential SF on a point of the face (200) closerto the location that the golfer most consistently impacts a golf ball.Such locations are generally nearer the face perimeter (210).

Therefore, in one embodiment a shortest distance along the face (200)from the first face point (300) to the face perimeter (210) is less thanthe Xcg distance, or even less than seventy-five percent of the Xcgdistance, or still further less than fifty percent of the Xcg distance.As one skilled in the art will appreciate, the golf club head (100)includes a bore having a center that defines a shaft axis (SA) whichintersects with a horizontal ground plane (GP) to define an origin pointand establish a vertical shaft axis plane (SAP). Further, the golf clubhead (100) has a center of gravity (CG) located: (i) vertically from theorigin point a distance Ycg; (ii) horizontally from the origin point adistance Xcg that parallel to the shaft axis plane (SAP) and the groundplane (GP); and (iii) a distance Zcg from the origin in a directionorthogonal to the shaft axis plane (SAP). In a similar embodiment ashortest distance along the face (200) from the first face point (300)to the face perimeter (210) is less than the Xcg distance, or even lessthan seventy-five percent of the Xcg distance or still further less thanfifty percent of the Xcg distance. In a further embodiment incorporatingboth a first permanent indicia (310) and a second permanent indicia(410), a vertical separation distance parallel to the shaft axis plane(SAP) from the first face point (300) to the second face point (400) isgreater than the Ycg distance. Another embodiment incorporating both afirst permanent indicia (310) and a second permanent indicia (410) has ahorizontal separation distance parallel to the shaft axis plane (SAP)from the first face point (300) to the second face point (400) that isgreater than the Xcg distance.

One particular embodiment incorporates a center face permanent indicia(252), a first permanent indicia (310), and at least one linear facemarking (280) having a linear face marking surface area (284). Here thesum of the center face indicia surface area (258) and the first indiciasurface area (340) is at least 25% of the linear face marking surfacearea (284), for the reasons previously disclosed. A further variation ofthis embodiment has a sum of the center face indicia surface area (258)and the first indicia surface area (340) that is also less than thelinear face marking surface area (284); while an even further variationhas a sum of the center face indicia surface area (258) and the firstindicia surface area (340) that is less than 50% of the linear facemarking surface area (284).

A similar embodiment incorporates a center face permanent indicia (252),a second permanent indicia (410), and at least one linear face marking(280) having a linear face marking surface area (284). Here the sum ofthe center face indicia surface area (258) and the second indiciasurface area (440) is at least 25% of the linear face marking surfacearea (284), for the reasons previously disclosed. A further variation ofthis embodiment has a sum of the center face indicia surface area (258)and the second indicia surface area (440) that is also less than thelinear face marking surface area (284); while an even further variationhas a sum of the center face indicia surface area (258) and the secondindicia surface area (440) that is less than 50% of the linear facemarking surface area (284).

Another embodiment of the golf club head (100) may have a thirdpermanent indicia (510) located on a face toe portion (260) of the face(200) indicative of a third CT, COR, of potential SF measured at a thirdface point (500), or calculated based upon at least one measured value,located on a face toe portion (260), as seen in FIG. 9. The thirdpermanent indicia (510) may be the only permanent indicia on the golfclub head (100), or may be incorporated with one or more of the otherdisclosed permanent indicia. In this embodiment the face (200) has athird thickness (520) at the third face point (500), and the thirdpermanent indicia (510) has a third indicia surface area (540). In oneparticular embodiment the golf club head (100) includes at least thefirst permanent indicia (310) and the third permanent indicia (510), andthe location of the first permanent indicia (310) is such that the firstthickness (320) is different than the third thickness (520). In anotherembodiment having both the first permanent indicia (310) and the thirdpermanent indicia (510), the first face point (300) is located higher onthe face (200) than the face center (250) and the third face point (500)is located lower on the face (200) than the face center (250), as seenin FIG. 9.

Similarly, another embodiment of the golf club head (100) may have afourth permanent indicia (610) located on a face heel portion (270) ofthe face (200) indicative of a fourth CT, COR, of potential SF measuredat a fourth face point (600), or calculated based upon at least onemeasured value, located on a face heel portion (270), also seen in FIG.9. The fourth permanent indicia (610) may be the only permanent indiciaon the golf club head (100), or may be incorporated with one or more ofthe other disclosed permanent indicia. In this embodiment the face (200)has a fourth thickness (620) at the fourth face point (600), and thefourth permanent indicia (610) has a fourth indicia surface area (640).In one particular embodiment the golf club head (100) includes at leastthe second permanent indicia (410) and the fourth permanent indicia(610), and the location of the second permanent indicia (410) is suchthat the second thickness (420) is different than the fourth thickness(620). In another embodiment having both the second permanent indicia(410) and the fourth permanent indicia (610), the second face point(400) is located lower on the face (200) than the face center (250) andthe fourth face point (600) is located higher on the face (200) than theface center (250), as seen in FIG. 9.

The golf club head (100) may have a max performance permanent indicia(710) that is indicative of the maximum CT or COR of the golf club head(100). Some times the maximum CT or COR of a golf club head (100) is notlocated at the face center (250). Therefore a golfer may want to knowthe location on the face (200) that has the maximum CT or COR. Thisembodiment involves identifying a max performance face point (700) onthe face (200) of the golf club head (100) within 0.75 inches of thecenter face (250) having a max CT or COR. This process involves firstidentifying the face center (250) and measuring the face center CT orCOR, then selecting at least two additional points on the face (200)within 0.75 inches of the center face (250) and measuring the CT or CORassociated with these two points, as seen in FIG. 10. The point with thehighest measured CT or COR value is then identified as the maxperformance face point (700), which may not correspond with the centerface (250) as seen in FIG. 11. As one skilled in the art willappreciate, this process is easily automated such that once the facecenter (250) is determined the golf club head (100), or the measurementtool, is automatically repositioned to any number of predeterminedlocations to have the actual CT measure for each location. The automatedsystem then identifies the predetermined location that produced the maxCT. While the first embodiment tested the center face (250) and twoadditional points, a further embodiment tests at least four pointswithin 0.75 inches of the center face (250). The max performancepermanent indicia (710) may then be created using any of the techniquesand relationships identified herein with respect to the other permanentindicia, but with a max performance point thickness (720), a maxperformance indicia depth (730), and a max performance indicia surfacearea (740).

Numerous methods may be used to apply the disclosed permanent indicia tothe golf club head (100). Such techniques include etching methods,oxidation techniques, peening methods, engraving techniques, mediablasting processes, machining methods, cutting processes, painting,application of durable inks and/or coatings. For example, etchingtechniques using laser processing, chemical processing, or through theuse of a photosensitive light-activated coating process may be used.Further, lasers also can be configured to produce markings that do notremove material to alter the depth of the face (200) or face coating(290); instead, the laser energy oxidizes the material of the face (200)or face coating (290), resulting in color change. This color changeleads to a marking that is visible without imparting spin to a golfball. The preferred laser type used is a Yttrium-Aluminum-Garnet (YAG)laser, such as the HM 1400 marketed by GSI Lumionics of Ottawa, Canada.Preferably, a 6-inch diameter lens having a 254 mm focal length is used.The impact surface 20 preferably is placed about 0.2 inches (5 mm) abovethe focal point of the lens, using a feed rate of 100 mm/s, a pulsefrequency of 20 kHz, and a power level of 80%. The golf club head (100)is fixtured under the laser normal to the beam axis. The permanentindicia marking pattern to be added to the face (200) can be loaded intothe laser apparatus control as an HPGL format file, and the pattern canbe burned onto the face (200) more than once if necessary to achieve adesired appearance.

While the golf club head (100) illustrated in FIGS. 1-11 is a driver,one skilled in the art will appreciate that golf club head (100) is notlimited to drivers and that the same principles apply to fairway woods,hybrids, as seen in FIG. 13, and irons as seen in FIG. 12.

In another embodiment of the golf club head (100) at least a perimeterportion of the crown adjacent a top portion of the face (200) has anarea that is at least 5% of the crown area has a bright, diffuselyreflecting surface, and at least a top perimeter portion of the face(200) has a dark diffusely reflecting surface area. In some embodiments,the bright, diffusely reflecting portion of the crown is white andincludes at least the upper facing portion of the crown, and the face(200) surface is a dark diffusely reflecting surface. In other examples,the bright, diffusely reflecting portion of the crown has a chroma valueof less than 5, and the face plate surface has a chroma value of lessthan 1. In additional representative examples, the bright, diffuselyreflecting portion of the crown has a brightness of at least 80. In someexamples, at least a portion of the crown adjacent a top perimeter ofthe face (200) has a semigloss surface with a chroma value of less than10 and a brightness of at least 50. In other examples, the brightdiffusely reflecting surface extends over at least 80% of the upwardfacing crown area or the crown surface has a CIELab brightness ofbetween 50 and 100, and a gloss value of less than 60 gloss units. Instill further examples, the dark, diffusively reflecting face (200)surface area has a CIELab brightness of less than 40 and a chroma ofless than 10 or the face plate has a gloss value of less than 60 glossunits. In other examples, a difference in L* values between the crownand the face (200) is high contrast for more than about 14.3%, 28.6%,42.9%, 57.1%, 71.4%, or 85.7% of the face distance.

In additional examples, a transparent matte coating is situated on atleast the upward facing portion of the crown, wherein the transparentmatte surface is a semigloss or low gloss surface, having a gloss valueof less than 60 gloss units. In some alternatives, at least the upwardfacing portion of the crown surface has a chroma value of less than 5 orless than 2. In still other examples, at least a top portion of the face(200) adjacent the crown has a black surface treatment that is asemigloss or low gloss surface. In some examples, the face (200) has agloss value of less than 60, 50, or 40 gloss units. In particularexamples, the black surface treatment has a chroma of less than 1 or 0.9and a brightness of less than 50 or 30. In some embodiments, the face(200) has a black surface treatment having a chroma of less than 1.0 anda brightness of less than 50, and at least the upward facing portion ofthe crown surface has a chroma value of less than 5 and a brightnessgreater than 85. Examples of diffuse surface treatments include paints,matte clear coats, clear coats, powder coatings, PVD, CVD, platings, ionplatings, electroplatings, ceramic coatings. Examples of paints includeurethane base coatings, pearl coats, epoxy based coatings, decals, inks,and primer coatings.

In some disclosed examples, surface gloss is referred to as semigloss orlow gloss. As used herein, semigloss refers to a range of 10 to 70 glossunits measured with respect to a standard 60 degree geometry. However,some examples include semigloss surfaces having surface gloss in rangeshaving lower limits of 10, 20, 30, 40, 50, or 60 gloss units and upperlimits of 20, 30, 40, 50, 60, or 70 gloss units. Similarly, low glosssurfaces include surfaces associated with standard gloss values of lessthan 10, 8, 5, 4, or 2 gloss units. Semigloss surfaces are typicallypreferred due to a chalky appearance that can be associated with lowgloss surfaces. Gloss measurements can be conveniently made withportable glossmeters such as the MICRO-TRI-GLOSS meters from BYKAdditives and Instruments.

Examples herein are described, for convenience, with respect to CIELabcolor space using L*a*b* color values or L*C*h color values, but othercolor descriptions can be used. As used herein, L* is referred to aslightness, a* and b* are referred to as chromaticity coordinates, C* isreferred to as chroma, and h is referred to as hue. In the CIELab colorspace, +a* is a red direction, −a* is a green direction, +b* is a yellowdirection, and −b* is the blue direction. L* has a value of 100 for aperfect white diffuser. Chroma and hue are polar coordinates associatedwith a* and b*, wherein chroma (C*) is a distance from the axis alongwhich a*=b*=0 and hue is an angle measured counterclockwise from the +a*axis. The following description is generally based on values associatedwith standard illuminant D65 at 10 degrees. This illuminant is similarto outside daylight lighting, but other illuminants can be used as well,if desired, and tabulated data provided herein generally includes valuesfor illuminant A at 10 degrees and illuminant F2 at 10 degree. Theseilluminants are noted in tabulated data simply as D, A, and F forconvenience. The terms brightness and intensity are also used in thefollowing description to refer to CIELab coordinate L*.

As seen in FIGS. 14- 18 another embodiment incorporates a removable facetemplate (800) that is uniquely marked with performance indicatingindicia indicating the actual measured characteristics of the face. Inone embodiment the removable face template (800) is attached to the golfclub head (100) so that a consumer can view the performance indicatingindicia of a particular golf club head (100) at a store prior topurchase and make a more educated purchasing decision. The consumer maythen remove the removable face template (800) prior to play and mayretain the removable face template (800) for their records of aparticular golf club head (100), and the consumer may use it duringfuture comparison shopping and/or as a selling point in the used golfclub market.

While the removable face template (800) may be sold with the golf clubhead (100) as a kit, in another embodiment the removable face template(800) exists in electronic form so that a potential consumer can viewthe electronic face templates of an existing inventory and purchase thespecific golf club head (100) associated with the desired electronicface template. Such an electronic ordering system may include theability to search, or filter, the electronic face templates in a numberof ways. For example a potential consumer may realize that their mostcommon mishit is an impact high on the face (200) in the face toeportion (260), therefore this consumer can sort the inventory to displayspecific golf club heads (100) that possess higher than average CTvalues in the high toe region. Similarly, a consumer could also sort theinventory for preferred characteristics in upper face toe portion (262),the lower face toe portion (264), the upper face heel portion (272), andthe lower face heel portion (274), as illustrated in FIG. 7. In oneembodiment a consumer may move an electronic representation of a golfball around on an electronic representation of the face (200) of a golfclub head (100) to indicate the location that the consumer most commonlyimpacts a golf ball during the swing. A computer system may then filterthe inventory to display golf club heads that have a higher than averageCT, COR, or potential SF in the region covered by the representation ofthe golf ball. In this embodiment “higher than average” means that thecomputer system uses the electronic face templates of at least 5 of thegolf club heads in inventory to determine an average regional CT, COR,or potential SF for the area of the face covered by the representationof the golf ball, then the computer system displays the golf club heads(100) in inventory that have at least one point on the face within thearea covered by the representative golf ball wherein the CT, COR, orpotential SF is greater than the average regional CT, COR, or potentialSF.

Further, the potential consumer can sort the inventory by the facecenter CT, COR, or potential SF value. For instance, a skilled golfermay only care about the face center CT, COR, or potential SF and may bewilling to pay a premium for a golf club head (100) that has a facecenter CT, COR, or potential SF above a certain value. Thus, theconsumer may sort the inventory to only display available golf clubheads (100) possessing a face center CT of at least 245 microseconds, orat least 250 microseconds, or at least 255 microseconds, or may onlywish to view golf club heads (100) that have been individually testedand posses a face center CT of the current absolute maximum conformingvalue of 257 microseconds. Many golfers are willing to pay a premium forperformance. In one embodiment the golf club head (100) may have a baseprice of $300 and a first tier performance characteristic premium of $20is added for those with a face center CT of at least a first tierperformance value such as 245 microseconds, while a second tierperformance characteristic premium of $40 is added for those with a facecenter CT of at least a second tier performance value such as 250microseconds, and a third tier performance characteristic premium of $60is added for those with a face center CT of at least a third tierperformance value such as 255 microseconds. Conversely, a bargain huntermay wish to play the same club as the professionals on TV yet may preferto save some money and have the base price reduces by a first tierperformance characteristic discount of $20 for a golf club head (100)with a face center CT of less than a first tier performance discountvalue such as 235 microseconds. Thus, an embodiment of this invention isan inventory management system containing at least one measure CT valueof each golf club head (100) in inventory and allows customers to sortthe inventory by the at least one measured CT value and/or a preferredCT distribution pattern.

Similarly, the consumer may sort the inventory to only display availablegolf club heads (100) possessing a face center COR of at least 0.822, orat least 0.826, or may only wish to view golf club heads (100) that havebeen individually tested and posses a face center COR of the currentabsolute maximum conforming value of 0.830. As previously noted, manygolfers are willing to pay a premium for performance. In one embodimentthe golf club head (100) may have a base price of $300 and a first tierperformance characteristic premium of $20 is added for those with a facecenter COR of at least a first tier performance value such as 0.825,while a second tier performance characteristic premium of $40 is addedfor those with a face center COR of at least a second tier performancevalue such as 0.828, and a third tier performance characteristic premiumof $60 is added for those with a face center COR of a third tierperformance value such as 0.830. Conversely, a bargain hunter may wishto play the same club as the professionals on TV yet may prefer to savesome money and have the base price reduces by a first tier performancecharacteristic discount of $20 for a golf club head (100) with a facecenter COR of less than a first tier performance discount value such as0.822. Thus, an embodiment of this invention is an inventory managementsystem containing at least one measure COR value of each golf club head(100) in inventory and allows customers to sort the inventory by the atleast one measured COR value and/or a preferred COR or potential SFdistribution pattern. The prior two paragraphs apply equally to thepotential smash factor (SF) but will not be repeated for the sake ofbrevity. The inventory management system may include all golf club headsof a particular manufacturer or OEM, or the inventory management systemmay be specific to a particular retailer, and may, or may not, belimited to only one brand of golf clubs.

Returning for the moment to embodiments with a physical removable facetemplate (800), since each removable face template (800) contains atleast one measured characteristic of a specific golf club head (100),the golf club head (100) includes a permanent club identifier (150),seen in FIG. 14, and the removable face template (800) has a templateidentifier (810) that is related to the permanent club identifier (150).For example, in one embodiment the permanent club identifier (150) is apermanent serial number on the golf club head (100), and the templateidentifier (810) is a marking that matches the serial number, or is avariation of the serial number such that a golfer can quickly identifythat a particular removable face template (800), or electronic facetemplate, was created for a particular golf club head (100).

Thus, all of the previous disclosure with respect to the permanentindicia on the face (200), namely the center face permanent indicia(252), the first permanent indicia (310), the second permanent indicia(410), the third permanent indicia (510), and the fourth permanentindicia (610), applies equally to the face template (800) embodimentsbut now the indicia is on the face template (800) as a center faceindicia (830), a first indicia (840), a second indicia (850), a thirdindicia (860), and a fourth indicia (870), instead of on the face (200)of the golf club head (100). For the sake of brevity, all of thedisclosure and embodiments related to each “permanent indicia” will notbe repeated for each face template indicia, however it is understoodthat all the variations possible with the permanent indicia on the faceare also possible with the template indicia on the face template.

The center face indicia (830) is indicative of the center face CT, COR,or SF, the first indicia (840) is indicative of the first CT, COR, orSF, the second indicia (850) is indicative of the second CT, COR, or SF,the third indicia (860) is indicative of the third CT, COR, or SF, andthe fourth indicia (870) is indicative of the fourth CT, COR, or SF. Thecenter face indicia (830), the first indicia (840), the second indicia(850), the third indicia (860), and/or the fourth indicia (870) caninclude numerals, letters, symbols, and/or changes in, or on, thesurface of the face (200) that are indicative of the associated measuredCT, COR, or SF, as described in detail herein with respect to thepermanent indicia.

In one embodiment the indicia, whether the permanent indicia (252, 310,410, 510, 610) or the removable indicia (830, 840, 850, 860, 870), isoriented so that it may be easily read by a consumer when the golf clubis in the typical sales presentation position, which is with the shaftpointed vertically at the ground and the face (200) pointed to theposition of a prospective purchaser viewing the sales display, see FIG.15. As one with skill in the art will recognize, a golf club head (100)has a design position in which it rests on a horizontal ground plane(GP) with a shaft axis (SA) at a predetermined lie angle. The axis ofthe indicia, which is a line under the indicia and parallel to thedirection of the indicia, is oriented at an angle θ from the shaft axis(SA), wherein θ meets the following relationship: [90+0.3*(lieangle)≧θ≧90−0.3*(lie angle)]. In this embodiment the potential consumermay quickly scan the indicia of an entire rack of golf clubs on displayand identify the golf club head (100) having the face performancecharacteristics that are desired.

The removable face template (800) has a template-to-face alignmentindicator (820) corresponding to an aspect of the face (200) to alignthe removable face template (800) with a portion of the face (200). Forexample in one embodiment the template-to-face alignment indicator (820)is simply a symbol, window, or opening in the removable face template(800), as seen in FIG. 15, that can be aligned with an element of thegolf club head (100) to repeatably position a portion of the facetemplate (800) on a portion of the face (200) and convey one or more ofthe performance indicia to a potential consumer, as well as theapproximate location that the performance characteristic was measured.For instance, in one embodiment the removable face template (800) istransparent so that when positioned on the face (200) a consumer maystill see aspects of the face (200) through the removable face template(800). Thus, in FIG. 15 the face center (250) is labeled on the golfclub head (100), and a similar marking is found on the removable facetemplate (800) as the template-to-face alignment indicator (820) suchthat when aligned with the face center (250), the center face indicia(830), the first indicia (840), and/or the second indicia (850) aredisplayed on the golf club head (100) in a position close to the pointon the face (200) that the measurements were performed.

In one particular embodiment the face (200) has at least one linear facemarking (280), and a portion of the template-to-face alignment indicator(820) matches a portion of the at least one linear face marking (280) sothe removable face template (800) is precisely positioned on the face(200) and a portion of the center face indicia (830) is within 0.25inches of the face center (250), the measurement position of the centerface CT or COR. The matching portion of the template-to-face alignmentindicator (820) may be a cut-out portion of the removable face template(820), or in a transparent embodiment it may just be a line, or seriesof marks, that matches a portion of one of more of the at least onelinear face marking (280), thereby aiding in alignment of the removableface template (820) so that the consumer can view the measuredperformance indicia and the approximate location of the measurement.Such indexing or placement of the removable face template (800) on theface (200) may also position the other indicia (840, 850, 860, 870)within 0.25 inches of the point on the face (200) where the associatedCT or COR was measured.

In another embodiment the template-to-face alignment indicator (820) isa portion of a template perimeter (825) configured to match a portion ofthe face perimeter (210) so the removable face template (800) isprecisely positioned on the face (200) and a portion of the center faceindicia (830) is within 0.25 inches of the face center (250). Stillfurther, a portion of the template perimeter (825) extends beyond theface perimeter (210) to form a template gripping region (827) that ahuman can easily grip to precisely align, or remove, the removable facetemplate (800), as seen in FIG. 15. In one particular embodiment theremovable face template (800) is a static cling vinyl, which in anotherembodiment is transparent. The removable face template (800) may be assimple as a face sticker.

In another embodiment the face (200) may have a permanent first facepoint indicator at the location of the first face point (300), such asthe dot shown in FIG. 15, and a portion of the template-to-facealignment indicator (820), with a corresponding dot or opening, alignswith the first face point indicator so the removable face template (800)is precisely positioned on the face (200) and a portion of the firstindicia (840) is within 0.25 inches of the first face point (300).Further embodiments may incorporate additional permanent face pointindicator(s) on the face (200) and corresponding template-to-facealignment indicator (820) for additional face points.

In another embodiment the method of identifying a particular point onthe face (200) of a golf club head (100), measuring a performanceindicative characteristic of the face (200) at the point, and eitherpermanently labeling the golf club head (100), or creating a unique facetemplate (800), may be automated in a method of mapping a plurality ofperformance variables of the face (200) of a golf club head (100),schematically represented in FIG. 17. The method includes the steps of:A) identifying a face center (250) on the face (200) of the golf clubhead (100) and storing the coordinates of the face center (250) in acomputer system (900); B) identifying a curvature profile of at least aportion of the face (200) of the golf club head (100) and storing thecurvature profile in the computer system (900); C) computing a3-dimensional face coordinate grid including at least a first face point(300) located on a face toe portion (260) of the golf club head (100),and a second face point (400) located on a face heel portion (270) ofthe golf club head (100), and storing the coordinates of the first facepoint (300) and the second face point (400) in the computer system(900); D) positioning the golf club head (100) or a measurementinstrument (1000) via the computer system (900) to align the measurementinstrument (1000) with the coordinates of the face center (250); E)activating the measurement instrument (1000) via the computer system(900) to determine a center face CT and storing the center face CT inthe computer system (900); F) positioning the golf club head (100) orthe measurement instrument (1000) via the computer system (900) to alignthe measurement instrument (1000) with the coordinates of the first facepoint (300); G) activating the measurement instrument (1000) via thecomputer system (900) to determine a first CT and storing the first CTin the computer system (900); H) positioning the golf club head (100) orthe measurement instrument (1000) via the computer system (900) to alignthe measurement instrument (1000) with the coordinates of the secondface point (400); and I) activating the measurement instrument (1000)via the computer system (900) to determine a second CT and storing thesecond CT in the computer system (900).

The step of identifying a face center (250) has been explained withreference to a USGA procedure using a template, however one skilled inthe art will appreciate that the same face center (250) may bedetermined by the computer system (900) and at least one image of thegolf club head (100), preferably a front elevation image looking at theface (200) or a full three-dimensional scanned image of the golf clubhead (100). In one particular embodiment specific to drivers, athree-dimensional scanned image of the golf club head (100) may beanalyzed with the computer system (900) and a best fit approximation ofthe roll curvature may be determined for the face (200) based upon thelocation of all scanned points that are within 22 mm above and below theface center. Within a given vertical plane that is normal to the face(200), the top edge (214) is then identified in the scanned data as thelowermost point above the face center (250) at which the scanned datadeviates by more than a threshold amount (e.g., 0.1 mm) from the bestfit roll curvature, and the leading edge (212) is identified as theuppermost point below the face center (250) at which the scanned datadeviates by more than the threshold amount from the best fit rollcurvature. A similar procedure may be used by the computer system (900)to identify the face perimeter (210), to calculate the striking surfacearea (232), to determine the bounds of the upper face toe portion (262),the lower face toe portion (264), the upper face heel portion (272), thelower face heel portion (278), and/or to determine the linear facemarking surface area (284).

Thus, in one embodiment the step of identifying the curvature profile ofat least a portion of the face (200) includes the step of imaging atleast a portion of the face with an imaging system (910) incommunication with the computer system (100) and storing the face imagedata in the computer system (900). Alternatively, the step ofidentifying the curvature profile of at least a portion of the face(200) includes the step of retrieving face profile data from apredefined face profile file stored in the computer system (900). As oneskilled in the art will appreciate, the face (200) of metal wood typegolf club heads (100) generally have a bulge and a roll defining a facecurvature. Further, it is not uncommon for golf club heads (100) to havemultiple bulge and roll values across the face (200).

The computer system (900) uses the face image data when positioning thegolf club head (100) or the measurement instrument (1000) via thecomputer system (900) to align the measurement instrument (1000) withthe coordinates of the first face point (300). A positioning system(1100), seen in FIG. 17, may accept instructions from the computersystem (900) to move the orient the golf club head (100), or it may moveand orient the measurement instrument (1000), or a combination of both.Thus, in one embodiment the step of positioning the golf club head (100)or the measurement instrument (1000) via the computer system (900) toalign the measurement instrument (1000) with the coordinates of thefirst face point (300), includes the step of adjusting the orientationof the golf club head (100) or the measurement instrument (1000) via thecomputer system (900) so the measurement instrument (1000) is measuringthe first CT approximately perpendicular to the first face point (300).Similarly regarding the second face point (400). Here, the step ofpositioning the golf club head (100) or the measurement instrument(1000) via the computer system (900) to align the measurement instrument(1000) with the coordinates of the second face point (400), includes thestep of adjusting the orientation of the golf club head (100) or themeasurement instrument (1000) via the computer system (900) so themeasurement instrument (1000) is measuring the second CT approximatelyperpendicular to the second face point (400). As the first face point(300) is on the face toe portion (260) and the second face point (400)is on the face heel portion (270), it is easy for one skilled in the artto appreciate how much the orientation must be adjusted to ensure thatmeasurement of the CT is occurring at the desired face point in anapproximately perpendicular orientation, as well as how time consumingsuch adjustments would be without an automated system.

As such, in one embodiment the method of mapping a plurality ofperformance variables of the face (200) of a golf club head (100)comprising the steps associated with identifying and measuring at leastone point for every 1 square inch of face area. A further embodimentcomprising the steps associated with identifying and measuring at leastone point for every 0.75 square inch of face area, while an even furtherembodiment comprising the steps associated with identifying andmeasuring at least one point for every 0.5 square inch of face area.Thus, while the prior disclosure described embodiments having five orless face points, the automated system disclosed can carry out the stepsnecessary to map 10 or more points on the face (200), while someembodiments as seen in FIG. 18 may map in excess of 30 face points toprovide the purchaser with a very unique map of the face performance.

In one embodiment the computer system (900) creates the mapping patternfor the face (200) based upon the face area, the shape of the face(200), and the desired number of face points. With the mapping patternestablished the computer system (900) computes a 3-dimensional facecoordinate grid including the coordinates for each face point in themapping patter, and the computer system (900) stores the coordinates inthe computer system (900). Next, the computer system positions the golfclub head (100) or the measurement instrument (1000) to align themeasurement instrument (1000) with the coordinates of an individual facepoint. Then, the computer system (900) activates the measurementinstrument (1000) via the computer system (900) to determine a specificface point CT and stores this CT in the computer system (900). Theprocess is then repeated for each desired face point. In yet a furtherembodiment the data gathered for each desired face point is analyzed bythe computer system (900) and a measured CT performance map is createdby the computer system (900). As previously mentioned, the measured CTperformance map may be similar to a topographic map with contour lines,or regions of common color or finish, and may be in the form ofpermanent indicia on the golf club head (100) or indicia on a facetemplate (800), as seen in FIG. 18. In one embodiment the computersystem (900) identifies the face point with the highest measured CT. Thecomputer system (900) then uses the measured CT values of the other facepoint to create a topographic map using measured CT values instead ofelevations.

Alternative embodiments may include additional permanent indicia in theform of contour lines to allow a consumer to view how the measure CTvaries across the face (200) of a particular golf club. Such additionalpermanent indicia contour lines may be shown in increments of 1microsecond, 2 microseconds, 5 microseconds, or even 10 microseconds. Inyet a further embodiment consists of variations of the face surface inlieu of a distinct a perimeter contour line, as described above, whiletransmitting the same information to the consumer regarding the actualmeasured CT, or CT profile, of a particular golf club head (100). Suchpermanent indicia surface variations may be achieved with a change insurface texture, brushing, polishing, gloss, and/or color. Anotherembodiment includes the step of creating an electronic face templatewith the computer system (900) and printing a removable face template(800) with a printer (1200) in communication with the computer system(900), as seen in FIG. 17.

A further embodiment includes the step of controlling a marking system(1300), schematically represented in FIG. 17 by a table top robotic armsystem carrying a laser, with the computer system (1000) to create (i) acenter face permanent indicia (252) indicative of the center face CT onthe face (200) near the face center (250), (ii) a first permanentindicia (310) indicative of the first CT on the face (200) near thefirst face point (310), and (iii) a second permanent indicia (410)indicative of the second CT on the face (200) near the second face point(410). In one particular variation the marking system (1300) is a laser,and the computer system (1000) controls the movement and activation ofthe laser to create the center face permanent indicia (252), the firstpermanent indicia (310), and the second permanent indicia (410). An evenfurther embodiment includes the step of having the computer system(1000) adjust the orientation of the laser at the first face point (310)so that a beam is approximately perpendicular to the face (200) at thefirst face point (310); and/or the step of having the computer system(1000) adjust the orientation of the laser at the second face point(410) so that the beam is approximately perpendicular to the face (200)at the second face point (410).

Another embodiment of the method includes the step of imaging a portionof the golf club head (100) to identify a permanent club identifier(150) on the golf club head (100), and storing the permanent clubidentifier (150) in the computer system (900). The computer system (900)then automatically creates the template identifier (810).

Another embodiment includes the step of creating an electronic facetemplate with the computer system (900) and printing a removable facetemplate (800) with a printer in communication with the computer system(900), wherein the removable face template (800) has a templateidentifier (810) related to a permanent club identifier (150) on thegolf club head (100), and a template-to-face alignment indicator (820)corresponding to an aspect of the face (200) to align the removable facetemplate (800) with a portion of the face (200), wherein the removableface template (800) includes a center face indicia (830) that isindicative of the center face CT, a first indicia (840) that isindicative of the first CT, a second indicia (850) that is indicative ofthe second CT, a third indicia (860) that is indicative of the third CT,and a fourth indicia (860) that is indicative of the fourth CT, andwherein the position of the center face indicia (830) on the removableface template (800) corresponds to location of the face center (250) onthe golf club head (100) when the template-to-face alignment indicator(820) is positioned on the face (200) to cooperate with thecorresponding aspect of the face (200), the position of the firstindicia (840) corresponds to location of the first face point (300) whenthe template-to-face alignment indicator (820) is positioned on the face(200) to cooperate with the corresponding aspect of the face (200), theposition of the second indicia (850) corresponds to location of thesecond face point (400) when the template-to-face alignment indicator(820) is positioned on the face (200) to cooperate with thecorresponding aspect of the face (200), the position of the thirdindicia (850) corresponds to location of the third face point (500) whenthe template-to-face alignment indicator (820) is positioned on the face(200) to cooperate with the corresponding aspect of the face (200), andthe position of the fourth indicia (840) corresponds to location of thefourth face point (600) when the template-to-face alignment indicator(820) is positioned on the face (200) to cooperate with thecorresponding aspect of the face (200). In another embodiment the stepof positioning the golf club head (100) or the measurement instrument(1000) via the computer system (900) to align the measurement instrument(1000) with the coordinates of the first face point (300), includes thestep of adjusting the orientation of the golf club head (100) or themeasurement instrument (1000) via the computer system (900) so themeasurement instrument (1000) is measuring the first CT approximatelyperpendicular to the first face point (300); and the step of positioningthe golf club head (100) or the measurement instrument (1000) via thecomputer system (900) to align the measurement instrument (1000) withthe coordinates of the second face point (400), includes the step ofadjusting the orientation of the golf club head (100) or the measurementinstrument (1000) via the computer system (900) so the measurementinstrument (1000) is measuring the second CT approximately perpendicularto the second face point (400); and the step of positioning the golfclub head (100) or the measurement instrument (1000) via the computersystem (900) to align the measurement instrument (1000) with thecoordinates of the third face point (500), includes the step ofadjusting the orientation of the golf club head (100) or the measurementinstrument (1000) via the computer system (900) so the measurementinstrument (1000) is measuring the third CT approximately perpendicularto the third face point (500), and the step of positioning the golf clubhead (100) or the measurement instrument (1000) via the computer system(900) to align the measurement instrument (1000) with the coordinates ofthe fourth face point (600), includes the step of adjusting theorientation of the golf club head (100) or the measurement instrument(1000) via the computer system (900) so the measurement instrument(1000) is measuring the fourth CT approximately perpendicular to thefourth face point (600).

Another embodiment includes the step of controlling a marking system(1300) with the computer system (1000) to create (i) a center facepermanent indicia (252) indicative of the center face CT on the face(200) near the face center (250), (ii) a first permanent indicia (310)indicative of the first CT on the face (200) near the first face point(310), (iii) a second permanent indicia (410) indicative of the secondCT on the face (200) near the second face point (410), (iv) a thirdpermanent indicia (510) indicative of the third CT on the face (200)near the third face point (510), and (v) a fourth permanent indicia(610) indicative of the fourth CT on the face (200) near the fourth facepoint (610). In an even further variation, the marking system (1300) isa laser, and the computer system (1000) controls the movement andactivation of the laser to create the center face permanent indicia(252), the first permanent indicia (310), the second permanent indicia(410), the third permanent indicia (510), and the fourth permanentindicia (610) . Still further, the step of having the computer system(1000) may adjust the orientation of the laser at the first face point(310) so that a beam is approximately perpendicular to the face (200) atthe first face point (310), approximately perpendicular to the face(200) at the second face point (410), approximately perpendicular to theface (200) at the third face point (510), and approximatelyperpendicular to the face (200) at the fourth face point (610).

Numerous alterations, modifications, and variations of the preferredembodiments disclosed herein will be apparent to those skilled in theart and they are all anticipated and contemplated to be within thespirit and scope of the instant invention. For example, althoughspecific embodiments have been described in detail, those with skill inthe art will understand that the preceding embodiments and variationscan be modified to incorporate various types of substitute and oradditional or alternative materials, relative arrangement of elements,and dimensional configurations. Accordingly, even though only fewvariations of the present invention are described herein, it is to beunderstood that the practice of such additional modifications andvariations and the equivalents thereof, are within the spirit and scopeof the invention as defined in the following claims The correspondingstructures, materials, acts, and equivalents of all means or step plusfunction elements in the claims below are intended to include anystructure, material, or acts for performing the functions in combinationwith other claimed elements as specifically claimed.

We claim:
 1. A golf club head (100) comprising: A) a face (200) having aface center (250) and a center face measured performance variable; B) acenter face permanent indicia (252) on the face that is indicative ofthe center face measured performance variable.
 2. A golf club head (100)of claim 1, wherein at least a portion of the face (200) has a facecoating (290), and the center face permanent indicia (252) is formed inthe face coating (290).
 3. A golf club head (100) of claim 2, whereinthe face coating (290) is a dark diffusely reflecting surface having achroma value of less than
 1. 4. A golf club head (100) of claim 2,wherein the center face permanent indicia (252) has a center facepermanent indicia L* value, the face (200) has a face L* value, and thegolf club head (100) has a volume and a loft, wherein the differencebetween the center face permanent indicia L* value and the face L* valueis related to the volume and the loft by the equationΔL*≦(volume)/100×(loft).
 5. A golf club head (100) of claim 4, whereinthe difference between the center face permanent indicia L* value andthe face L* value is related to the volume and the loft by the equationΔL*≦(volume)/125×(loft).
 6. A golf club head (100) of claim 4, whereinthe difference between the center face permanent indicia L* value andthe face L* value is less than
 25. 7. A golf club head (100) of claim 4,wherein the face (200) has a striking surface area (232) and at leastone linear face marking (280), wherein at least a portion of the atleast one linear face marking (280) has a linear face marking L* value,and the difference between the linear face marking L* value and the faceL* value is at least
 30. 8. A golf club head (100) of claim 1, whereinthe center face measured performance variable is a center face CORmeasured upon completion of the golf club head (100), and the centerface permanent indicia (252) includes numerals representing the centerface COR.
 9. A golf club head (100) of claim 1, wherein the center facemeasured performance variable is a center face CT measured uponcompletion of the golf club head (100), and wherein the center facepermanent indicia (252) includes numerals representing the center faceCT.
 10. A golf club head (100) of claim 1, wherein golf club head (100)has a loft, the center face permanent indicia (252) has a permanentindicia surface roughness, and the face (200) has a face surfaceroughness and a face area, and wherein the difference between thepermanent indicia surface roughness and the face surface roughness isrelated to the loft and the face area by the equation ΔSR≧60*(facearea)/(loft), for lofts less than 25 degrees, wherein the permanentindicia surface roughness is greater than the face surface roughness.11. A golf club head (100) of claim 10, wherein the permanent indiciasurface roughness is at least 10 μin greater than the adjacent facesurface roughness.
 12. A golf club head (100) of claim 10, wherein thepermanent indicia surface roughness is at least twice the adjacent facesurface roughness, and the permanent indicia surface roughness is lessthan fifteen times the adjacent face surface roughness.
 13. A golf clubhead (100) of claim 10, wherein for lofts of at least 25 degrees thedifference between the face surface roughness and the permanent indiciasurface roughness is related to the loft and the face area by theequation ΔSR≦200*(face area)/(loft), wherein the face surface roughnessis greater than the permanent indicia surface roughness.
 14. A golf clubhead (100) of claim 1, further including a first permanent indicia (310)located on a face toe portion (260) of the face (200) indicative of afirst measured performance variable measured at a first face point (300)located on a face toe portion (260), wherein the face (200) has a firstthickness (320) at the first face point (300), and the first permanentindicia (310) has a first indicia surface area (340).
 15. A golf clubhead (100) of claim 14, wherein the face (200) has a center facethickness (254) at the face center (250), and the first thickness (320)is different than the center face thickness (254).
 16. A golf club head(100) of claim 14, wherein the first face point (300) is located higheron the face (200) than the face center (250).
 17. A golf club head (100)of claim 14, wherein the golf club head (100) includes: (a) a borehaving a center that defines a shaft axis (SA) which intersects with ahorizontal ground plane (GP) to define an origin point and establish avertical shaft axis plane (SAP); and (b) a center of gravity (CG)located: (i) vertically from the origin point a distance Ycg; (ii)horizontally from the origin point a distance Xcg that parallel to theshaft axis plane (SAP) and the ground plane (GP); and (iii) a distanceZcg from the origin in a direction orthogonal to the shaft axis plane(SAP); (c) wherein the face (200) has a face perimeter (210) and ashortest distance along the face (200) from the first face point (300)to the face perimeter (210) is less than the Xcg distance.
 18. A golfclub head (100) of claim 17, wherein the shortest distance along theface (200) from the first face point (300) to the face perimeter (210)is less than seventy-five percent of the Xcg distance.
 19. A golf clubhead (100) of claim 14, further including a second permanent indicia(410) located on a face heel portion (270) of the face (200) indicativeof a second measured performance variable measured at a second facepoint (400) located on a face heel portion (270), wherein the face (200)has a second thickness (420) at the second face point (400), and thesecond permanent indicia (410) has a second indicia surface area (440).20. A golf club head (100) of claim 19, wherein the face (200) has acenter face thickness (254) at the face center (250), and the secondthickness (420) is different than the center face thickness (254).